Safety device for automatically-locking locks.



A. LEISTLER. SAFETY DEVICE FOR AUTOMATICALLY LOOKING LOOKS.

APPLICATION FILED JAN. 31, 1910. I

' Patented Sept. 20, 1910.

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ALOIS LEISTLER, 0F HOLLENSTEIN A. D. YBBS, AUSTRIA-HUNGARY.

SAFETY DEVICE FOR AUTOMATICALLY-LOCKING LOCKS.

Specification of Letters Patent.

Application filed January 31, 1910.

Patented Sept. 20, 1910. Serial No. 541,050.

To all whom it may concern:

Be it known that I, ALois LEISTLER, landowner, a subject of the Emperor of Austria- Hungary, and a resident of Hollenstein a. d. Ybbs, Lower Austria, in the Empire of Austria-Hungary, have invented Improvements in or Relating to Safety Devices for Automatically- Locking Locks; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the known automatieally locking locks in which the bolt is retained in its pushed back position by a locking member subjected to the action of a latch in such a manner that when the door or the like is closed the latch is pressed inward and releases this locking member, whereupon the bolt is displaced into its looking position by spring action. Locks of this kind which are provided with a number of tumblers are constructed in accordance with thepresent invention in such a manner that it is impossible for an unauthorized person to unlock the look. This result is attained owing to the fact that the locking member is provided with an arm or bar extending transversely over the tumblers and provided with recesses for the entrance of the tumblers which correspond to the steps on the bit of the key so that if when an attempt is made to unlock the lock by means of a skeleton key or the like, one of the tumblers is lifted too high, the locking member is disengaged from the bolt and consequently the pressed back bolt is at once shot back into its locking position, while when the tumblers are not all lifted to a sufficient height it is impossible to open the look at all.

The invention is illustrated by way of example in the accompanying drawing in which:

Figure 1 illustrates a lock in elevation with lock plate removed and showing an embodiment of the safety device. Fig. 2 is a corresponding cross section on the line CC in Fig. 1, and Fig. 3 illustrates another embodiment of the device likewise in cross section.

I The lock consists of the latch 1 in which the end of a locking plate 2 rotatable about the pivot 6, engages. On its lower face this locking plate has teeth or notches 11 by means of which the projection 12 provided on the bolt 3 and consequently the bolt itself may be retained in one of the pressed back positions. Tumblers 4 act on the bolt 3 engaging in a rearwardly ascending set of teeth 5 in the bolt; they are depressed by springs 7. This known form of lock acts in the following manner. hen the door or the like provided with the lock, the bolt 3 of which is retained in the drawn back position by engagement of the parts 11 and 12, is closed or slammed, the chamfered latch 1 on striking the lock nab is pressed back and owing to the resulting lifting of the locking plate 2 the bolt 3 is released and under the action of the spring 15 it springs forward and locks the door. The tumblers 4 slide over the inclined teeth 5 on the bolt 3 during this movement. The latch 1 returns to the position represented in Fig. 1 under the influence of the spring 13 carrying the locking plate 2 with it. WV hen the lock is unlocked by means of the key 8 the retractively displaced bolt is again retained in its drawn back position by the engagement of the projection 12 in the teeth 11 on the plate 2.

Any unauthorized opening of the lock is rendered difficult owing to the fact that the ends 9 of the tumblers 4 engage in slots 10 in the bolt so that it'is difficult to act upon the tumblers by means of a false key or the like owing to the protection afforded to them by the walls of the bolt.

The safety device proper in accordance with the present invention resides in the fact that an arm 14 proceeds from the locking plate 2 extending transversely over the tumblers 4; this arm is provided on its under side with notches 16 corresponding to the steps of the key of the look so that when the lock is-opened by means of its proper key, neither the arm nor the locking plate is acted upon. If, however, an attempt is made to open the lock by means of a false or skeleton key or the like when any of the tumblers are lifted too high the arm 14 and consequently the locking plate 2 are lifted by this tumbler so that the projection 12 on the bolt 3 is disengaged from the teeth 11 on the locking plate 2, the result being that the bolt at once springs back into the locking position. If, on the other hand even one of the tumblers is lifted too little it retains the bolt fixed in the locking position and the lock remains locked. Owing to the fact that with this arrangement of the lock it is impossible to discover how high each separate tumbler should be lifted the lock is rendered perfectly secure. The security can be still further increased if one or more of the tumblers for example the middle tumbler 17 is constructed without a locking hook, and as shown in Fig. 3 either bears against the arm, or if lifted to a less extent than the other tumblers strikes against it, while the key is not provided with a step for this tumbler so that when the lock is opened it remains entirely unacted upon and thus constitutes a sort of blind tumbler. If, however, this tumbler is lifted even to the slightest extent by an unauthorized person the locking plate is displaced from the locking position and thus renders it impossible to open the look.

What I claim as my invention and desire to secure by Letters Patent is:

An automatic safety lock of the character described. comprising a pivoted locking plate engaging with its free end a spring actuated latch, and being provided with teeth upon its lower face, a bolt having a projection engaging said teeth, a spring engaging the rear end of said bolt adapted to press the same into its locking position, and spring actuated tumblers engaging with their hooked ends slots in said bolt, and an arm upon said locking plate, extending transversely over the tumblers and being provided on its underside with notches corresponding to the steps of the key for said lock, substantially as described, and for the purpose set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ALOIS LEISTLER.

Witnesses:

KARL REHRAK, AUGUST FUGGER. 

